Kentucky State Police are searching for motive as they investigate the fatal shooting of a district judge by a sheriff after the two had an argument inside the judge’s chambers, according to police.

Letcher County Sheriff Shawn M. Stines, 43, was taken into custody at the scene without incident, police said. He was charged with one count of first-degree murder.

A judge in a rural Kentucky county was shot and killed in his courthouse chambers Thursday, and the local sheriff was charged with murder in the slaying, police said.